Portable electronic devices, such as two-way radios, typically include a rechargeable battery that is removably connected to the electronic device. Ordinarily, the battery is electrically coupled to the electronic device via an electrical interface that includes a portion on the electronic device and a portion on the battery. The electrical interface generally has movable contacts and fixed contacts. The movable contacts facilitate the establishment of electrical contact between both portions of the electrical interface by accommodating for variations due to tolerances and like.
Fixed contacts are typically more inexpensive to incorporate within a product than are movable contacts. Hence, it is customary to find fixed contacts employed on the battery to minimize product costs. Such electrical contacts have been traditionally formed using discrete contact elements electrically coupled to circuitry within the battery. The discrete contacts may be affixed directly to a circuit carrying substrate used in the internal operations of the battery, or may be affixed to a battery housing member using a rivet, or other type of fastener.
Movable contacts are generally incorporated within that portion of the electrical interface on the host device. A movable contact tends to have more parts than a fixed contact, and thus is more expensive to incorporate into a product. Prior art approaches to movable contacts include the use of pogo pins, cantilever contacts, springs, and the like. By incorporating such movable contacts on the electronic device, the more expensive portion of the electrical interface can be incorporated into the higher priced unit, i.e., the electronic device. As a user is likely to purchase several batteries for each electronic device purchased, it is thought that by incorporating the less expensive component of the electrical interface on the battery, the overall cost to a customer is reduced.
It has been observed that a movable contact is much more susceptible to damage from corrosion, shock, jamming, and the like. When such contact is damaged, the electronic device must be taken out of service for repair or replacement of the contact. This deprives the user of the use of the electronic device, and thus runs contrary to the objective of reducing overall expense to the user. Fixed contacts, which have no movable parts, can be formed to be less prone to damage through normal use.
In an electrical interface, it is desirable to incorporate the reliability of fixed contacts while providing for the tolerance accommodation afforded by movable contacts. Therefore, there exists a need to provide for the incorporation of fixed and movable contacts in an electrical interface between an electronic device and a removable battery that is reliable and cost effective.